4 oxygen sensor codes

[lugnut]

i have been working on a 1999 gmc one ton box van with a 350 eng.
100,000 miles on it. truck came in running bad. service eng. soon lite on. ck codes and got 4 codes one for each o2 sensor. cleared the codes ran the truck till it started to run bad and service light came on and got only one sensor code. replaced that sensor (o2 ) and replaced plugs wires cap and rotor just beacuse the truck has 100,000 on original.still hade same problem. truck starts to run bad and codes for all 4 o2 sensors come up. replaced all 4 sensors. still having same problem.




problem found trans when hot. engine under load, oil hot, intermitently will shift up 2 gears instead of one. overloading eng. ang sending the codes

[greasemonkeys69]

Originally Posted by lugnut

i have been working on a 1999 gmc one ton box van with a 350 eng.
100,000 miles on it. truck came in running bad. service eng. soon lite on. ck codes and got 4 codes one for each o2 sensor. cleared the codes ran the truck till it started to run bad and service light came on and got only one sensor code. replaced that sensor (o2 ) and replaced plugs wires cap and rotor just beacuse the truck has 100,000 on original.still hade same problem. truck starts to run bad and codes for all 4 o2 sensors come up. replaced all 4 sensors. still having same problem.




problem found trans when hot. engine under load, oil hot, intermitently will shift up 2 gears instead of one. overloading eng. ang sending the codes

how did you fix it??